The best two Remote Desktop apps available at this days are Splashtop and Crazy Remote, both running 30fps so it's possible to watch videos and play games without any lag. Both are available on iOS and Android,but not on wp7 :(

I don't trust any 3rd part Remote Desktop app with my macihnename, username, password being entered in their UI. How do I know these details are not getting copied off to some server?
Microsoft need to release an official Remote Desktop app for WP7 or include such feature as part of WindowsPhone8.
Only then would I trust and use a RD solution on my phone.